Solid oxide proton conductors display lower activation energy than conventional oxygen-ion conductorswith a good development prospect. BaZr0.1Ce0.7Y0.2O2.9(BZCY)-(Li/Na)2CO3 composite electrolytes were prepared with BZCY powders synthesized by homogeneous coprecipitation. The structure and electrical properties of composite electrolytes were preliminarily studied. The conductivities of the composites reach 0.095Scm-1 at 600 oC and 0.071Scm-1 at 450oC in air, 0.126Scm-1 and 0.075Scm-1 in humidified hydrogen. The maximum power densities reach 741mWcm-2 at 600 oC and 258mWcm-2 at 450 oC.